The invention relates to a method for producing and patterning organic field-effect transistors (OFETs).
Polymeric integrated circuits based on OFETs are used for microelectronic mass applications and disposal products such as identification and product tags. A tag is e.g. an electronic bar code of the kind provided on merchandise or on luggage. In this case, the excellent operating behavior of silicon technology can be dispensed with, but by the same token low producing costs and mechanical flexibility should be ensured. The devices such as e.g. electronic bar codes are typically disposable products and are of interest economically only if they are produced in inexpensive processes.
To date, owing to the production costs, only the conductor layer of the OFET has been patterned since the patterning can only be realized using a two-stage process (“lithography method” cf. in this respect Applied Physics Letters 73(1), 1998, p. 108.110 and Mol. Cryst. Liq. Cryst. 189, 1990 p. 221-225) with firstly whole-area coating and subsequent patterning, which is material-specific, moreover. “Material specificity” means that the process described, with the photochemical components mentioned, only functions on the conductive polymer polyaniline. A different conductive polymer, e.g. polypyrrol, cannot readily be patterned in this way.
The lack of patterning of the other layers, such as the semiconducting layer and the insulating layer made of functional polymers, leads to a significant reduction in performance of the OFETs obtained, but it is dispensed with for cost reasons.